I have already posted some time ago a post related to the same topic (see here).

Today, I want to explain the easiest way to create an asynchronous replica from an existing MySQL instance, that this time has already data !

The Existing Situation and the Plan

Currently we have a MySQL server using 8.0.17 and GTID enabled on mysql1. mysql2is a single fresh installed instance without any data.

The plan is to create a replica very quickly and using only a SQL connection.

Preliminary Checks

First we verify that mysql1 has GTID enabled. If not we will enable them:

mysql> select @@server_id,@@gtid_mode,@@enforce_gtid_consistency;
+-------------+-------------+----------------------------+
| @@server_id | @@gtid_mode | @@enforce_gtid_consistency | …

With MySQL Shell 8.0.17, a super cool new feature was released: the MySQL Shell Extensions & Plugins !

You will be able to write your own extensions for the MySQL Shell. You may already saw that I’ve written some modules like Innotop or mydba for MySQL Shell.

However those plugins were written in Python and only accessible in Python mode. With the new Shell Extensions Infrastructure, this is not the case anymore.

Also, this allows you to populate the help automatically.

Extensions are available from the extglobal object.

…

Create a MySQL InnoDB Cluster using MySQL 8.0 has always been very easy. Certainly thanks to MySQL Shell and server enhancements like SET PERSIST and RESTART statement (see this post).

The most complicated part to deal with was the existing and none existing data. In fact GTID sets must be compatible.

Let me explain that with some examples:

Example 1 – empty servers

If you have empty servers with GTID enabled, manually creating credentials to connect to each MySQL instances will generate GTIDs that will prevent nodes to …

MySQL Roles are becoming more and more popular. Therefor, we receive more and more questions related to them.

First I encourage you to read this previous 2 posts:

• MySQL 8.0 Roles and GraphML
• MySQL 8.0: Listing Roles

In this post, I will share you some queries I find useful when using MySQL Roles.

Listing the Roles

The first query allows you to list the Roles created on your MySQL Server and if they are assigned to users, and how many:

SELECT any_value(User) 'Role Name', 
       IF(any_value(from_user) is NULL,'No', 'Yes') Active,
       count(to_user) 'Assigned  …

MySQL supports different types of Indexes. They depend on the storage engine and on the type of data. This is the list of supported indexes:

• B-trees (the most common)
• R-trees (for spatial data)
• Hashes (for Memory engine)
• Inverted (for InnoDB Full Text)

Best Practices

My recommendation are valid for InnoDB storage engine. I won’t talk about MyISAM. There are some best practices to follow when designing your tables. These are the 3 most important:

At the end of the month, some engineers of the MySQL Team will be present in Austin, TX !

We will attend the first edition of Percona Live USA in Texas.

During that show, you will have the chance to meet key engineers, product managers, as well as Dave and myself.

Let me present you the Team that will be present during the conference:

The week will start with the MySQL InnoDB Cluster full day tutorial by Kenny and myself. This tutorial is a full hands-on tutorial where we will start by migrating a classical asynchronous master-replicas topology to a new MySQL InnoDB Cluster. We will then experience …

With MySQL Shell 8.0.16, a new very interesting feature was released: the Reporting Framework.

Jesper already blogged about it and I recommend you to read his articles if you are interested in writing your own report:

• https://mysql.wisborg.dk/2019/04/26/mysql-shell-8-0-16-built-in-reports/
• https://mysql.wisborg.dk/2019/04/27/mysql-shell-8-0-16-user-defined-reports/

I this post, I will show you one user-defined report that can be used to monitor your MySQL InnoDB Cluster / Group Replication.

Preparation

Before being able to use the report, you need to download 2 files. The first one is the …

We saw yesterday that when an issue (like network splitting), it’s possible to remain with a partitioned cluster where none of the partition have quorum (majority of members). For more info read how to manage a split-brain situation.

If your read the previous article you notice the red warning about forcing the quorum. As an advice is never too much, let me write it down again here : “Be careful that the best practice is to shutdown the other nodes to avoid any kind of conflicts if they reappear during the process of forcing quorum“.

But if some network problem is happening it might not be possible to shutdown those other nodes. Would it be really bad ?

YES !

Split-Brain

Remember, we were in this situation:

We …

Why migrating to MySQL 8.0 ?

MySQL 8.0 brings a lot of new features. These features make MySQL database much more secure (like new authentication, secure password policies and management, …) and fault tolerant (new data dictionary), more powerful (new redo log design, less contention, extreme scale out of InnoDB, …), better operation management (SQL Roles, instant add columns), many (but really many!) replication enhancements and native group replication… and finally many cool stuff like the new Document Store, the new MySQL Shell and MySQL InnoDB Cluster that you should already know if you follow this blog (see these TOP 10 for features for developers and this TOP 10 for DBAs & OPS).

Not anymore a drop in replacement !

…

On this article, I will show you how to migrate your wordpress database from the MariaDB on CentOS to the real MySQL.

Why migrating to MySQL 8.0 ?

MySQL 8.0 brings a lot of new features. These features make MySQL database much more secure (like new authentication, secure password policies and management, …) and fault tolerant (new data dictionary), more powerful (new redo log design, less contention, extreme scale out of InnoDB, …), better operation management (SQL Roles, instant add columns), many (but really many!) replication enhancements and native group replication… and finally many cool stuff like the new Document Store, the new MySQL Shell and MySQL InnoDB Cluster that you should already know if you follow this …